Felis Britannica is the United Kingdom Member of the Fédération Internationale Féline (FIFe).
FB registers and shows cats under the rules of FIFe. Registrations and show awards at FIFe International Shows are recognised by all other member of FIFe.
Felis Britannica is itself a federation of cat clubs all over the UK which organise shows licenced by FB. Individuals can be members of several clubs, but to register pedigree kittens, you have to nominate one club to handle your registrations and to claim show awards.